Of course I've been painting this to match the rest of my Tau. I still have quite a bit of the colors I use. I don't know what I'm going to do when I run out of Fenris Grey. Also my Astronomicon Grey isn't in great shape.
It's actually a lot of work to paint this large of a model, with all this detail, with a brush. But using an airbrush is also not feasible since there is so much black areas as well.
After the primer I dry brushed the entire model with Codex Grey, to save time doing edge highlighting on the black. It turned out just about perfect.